The purpose of this project is the analysis of the effects of neonatal OT manipulations on subsequent social bonding, aggression and other aspects of social interactions in prairie voles. A second phase of this project will examine the responses of the HPA axis to selected challenges in both adulthood and during development. The third purpose of this project is to examine mechanisms through which OT is capable of affect either behavior of the HPA axis. This will be accomplished by sensitivity of neonatally manipulated animals to respond to OT in adulthood.